The skin possesses the function of protecting the body from various forms of stress due to the external environment, but if this body maintenance function becomes unbalanced, various forms of skin conditions appear, such as chapped skin and scabies.
As the majority of these skin conditions are accompanied by itching, this itching leads to skin pruritis, which can frequently exacerbate the original skin condition.
There are individual differences in the degree of itching in such cases of pruritic skin diseases and cases of skin pruritis, ranging from that which is extremely mild to that which is extremely severe. In addition, as a sebum deficiency, which is one cause of pruritis, is observed to some degree in the case of elderly subjects, there are cases in which urea ointment and zinc oxide ointment, etc. are used because of the moisture effects thereof.
Moreover, steroid preparations, anti-histamines and Crotamiton preparations, etc., have been widely used in the past as antipruritics.
Nevertheless, itching accompanying liver and renal disfunction and malignant tumors, metabolic disorders and senile pruritis, and pruritic skin diseases such as atopic dermatitis, eczema and urticaria, against which these antipruritics are unable to demonstrate antipruritic effects, are becoming a serious problem in the clinical setting.
As these diseases are frequently accompanied by serious itching, the particular condition may be exacerbated due to scratch to the skin resulting from that itching. As such, an antipruritic able to demonstrate adequate antipruritic effects has been long awaited. Furthermore, steroid preparations, antihistamines, and so on may cause problems due to adverse side effects, in certain cases.